I've had good success using Ubiquity a single Unifi AC lite AC lite PoE access point. I get very stable wifi streams using channels with two ATV4 and HDHR Prime.
I've had a few episodes where I lost connection or had distorted streams which I think was related to demands from a other wifi users. I have had it set-up for a few days, but I think this looks like it could be a great whole house solution.
The devices start at $90 and come with a PoE injector. It works much better than my AC router and looks great on the ceiling. It's eady to set up with an existing router and iphone app to configure. I've had no luck configuring with their W10 Controller program. I believe the full controller app would allow for prioritization for the ATV4s but I can't get it working to find out. Support from Ubiquity is only chat and user groups.
Here's a link to what I'm using: